As network scale and scope enlarge quickly, people's activities rely on network services more and more, and the network load becomes heavier and heavier; whether from the viewpoint of network subscribers or from the viewpoint of network administrators, it is increasingly urgent to manage networks effectively.
In today's network environments, there are mainly 3 approaches for management of network devices, which are described as follows respectively.
The first approach is to connect a network management device directly to network devices to be managed via serial ports, to implement configuration management of the network devices. The major advantage of the approach lies in its simple management means, without needing other additional devices; furthermore, since the network devices to be managed are connected directly via serial ports, it is unnecessary to allocate management IP addresses to them when they are configured, and thereby save IP resource. However, since the network devices may be distributed in a large area, in particular, in a telecom network, there are a large number of data devices distributed across the network, such a management approach will inevitably bring difficulties to maintenance work and cause heavy workload.
The second approach is to manage TCP/IP network devices remotely on the basis of the Single Network Management Protocol (SNMP) or the terminal emulation protocol TELNET. Compared with the first approach, since the network management procedure is implemented on a standard IP protocol stack, it is simple to implement and light in workload; in addition, it has little correlation with other devices, so that the administrator can implement remote management of network devices to be managed through a network management terminal or TELNET emulation terminal; however, the major disadvantage is: each network device to be managed has to be allocated with a public network IP address, which will result in waste of IP address resource; especially, in a telecom network with a large number of devices, that disadvantage is more severe.
The last approach is put forth on the basis of the second approach; its core idea is to take the serial numbers of network devices allocated by the device manufacturer as device addresses to implement management of network devices; therefore, such an approach can save IP address resource; however, it is applicable to devices from a specific manufacturer and the network management program runs on a private protocol stack and thereby the management protocol nearly has no openness and is unable to implement unified management of network devices from different manufacturers.